1. Field of the Invention
The present invention concerns the partial conversion of a pre-diffused logic circuit, as well as the converted integrated circuit in which the transistors of one or more logic cells are used in order to set up a power amplifier, located among the logic cells.
2. Description of the Prior Art
It is known that pre-diffused integrate circuits are circuits comprising components, namely simple components like transistors or more complex ones like logic operators, that are not mutually interconnected. They are non-specific circuits that are customized according to the needs of the users, by means of one or more metallizations of interconnections.
However, from the very moment of their designing, pre-diffused circuits have a certain orientation: some are designed to become analog circuits while others are designed to become logic circuits. In the case of logic circuits, the pre-diffused transistors have low noise and low power characteristics, so that the logic "core" of the chip of semiconductor material has to be surrounded by a belt of amplifier interface circuits.
If a logic operator has to possess a high fan-out, either because it is addressed to a plurality of other logic operators or because it is connected by a long connection, it becomes necessary to come out of the "core" of the chip to amplify the signals by a so-called "buffer" circuit, and then to re-enter the core towards the logic operators. There is no optimization of the interconnections, and the long connections attenuate the signals, or set up interference.